The present invention relates to a clamp for holding a long, narrow shaped elongated member such as a pipe, tube or wire harness onto an attaching member such as the body panel or the like of an automobile, in particular, a vibration-proof clamp that neither transmits vibrations from the elongated member such as a pipe, tube or wire harness to an attaching member such as the body panel or the like nor transmits vibrations from the attaching member such as the body panel or the like to the elongated member such as a pipe, tube or wire harness.
A pipe clamp by which a pipe is mounted removably to an attaching member is provided with a clamp part that holds the pipe and a main body part that is fixed on an attaching member such as the body panel of an automobile; the pipe is held by the clamp part and the main body part is fixed to the attaching member. The clamp part has an open portion that receives a pipe on the top and is constructed to accommodate the pipe in a U-shaped space formed by a pair of side walls and a bottom, holding it so that the accommodated pipe does not escape from the clamp part. The main body part has a fixing means for being mounted removably to the attaching member such as a body panel or the like and is fixed to the attaching member such as the body panel of an automobile or the like.
Because of the pulsations of the fluid passing through the interior of the pipe, the pipe will be caused to pulsate. It is necessary to avoid the transmission of such pulsations to the auto body via the pipe clamp. Also, it is necessary that the pulsations of the auto body not be transmitted to the pipe via the pipe clamp.
To accomplish this, pipe clamps exist that are highly vibration-proof and in which the contact surface of the unit holding the pipe is made of rubber or a soft resin. In such pipe clamps, the pipe is not in direct contact with the holding member made of hard resin, and it becomes difficult to transmit the pulsations of the pipe to the auto body. Also, the number of parts is comparatively small. However, as rubber or soft resin is flexible, it stretches easily, and the ability to hold the pipe is inferior to pipe clamps of prior art.
Also, there is a pipe clamp in which the clamp part holding the pipe and main body part fixed on the attaching member are formed by a hard resin. An elastic member made of rubber or soft resin is interposed between the clamp part and the main body part. In such a pipe clamp, it is difficult to transmit pulsations from the pipe part to the main body part. Such a floating type clamp is effective in absorbing pulsations. However, construction becomes complicated, and a problem arises in that it is difficult to combine the soft elastic member with the hard clamp part and the main body part.
The vibration-proof clamp of the floating type has a complicated construction and tends to have a large number of components. Due to insert molding or dichroic molding, a molding machine for insert molding or dichroic molding and a die are necessary.
Patent Document 1 discloses a vibration-proof clamp that provides a twofold construction of a main body part from a hard member of a shape in which an insertion aperture opens and a vibration-proof part that has a holding body that is formed with a soft member and grasps the tube body. The main body part, with a pressing force from the tube body passing through the insertion aperture, has a retaining member that is bent. The holding body of the vibration-proof part, as it joins with the inner wall of the main body part, sets up the separation of a cavity part on the main body part and holds the tube part by fitting.
Inasmuch as the vibration-proof clamp of Patent Document 1 forms a cavity between the main body part and the holding part, it can effectively control the transmission of vibrations and increase its resistance to vibration. However, regarding the vibration-proof clamp of Patent Document 1, because the main body part is set in a mold, followed by injecting and solidifying resin to form the holding body, i.e. because of insert molding or dichroic molding, a molding machine for insert molding or dichroic molding and a die are necessary.
Also, the pipe (tube body), in general, uses a pipe assembly automated machine and imposes the pipe into the vibration-proof clamp. Since the holding body is made of a soft member, it will be difficult for the pipe to slide; there is a cavity directly under it, and it is of concern that the holding body will be stretched and fracture, or will peel off from the main body part made of hard resin.
Patent Document 2 discloses a grommet having a main body that has an attaching concave part for attaching and holding a linear held body such as a pipe, and a fixed member that supports a main body and fixes it in a prescribed position. The holding contact part of the main body is insulated with a thin-layered cushion. The holding body is protected from vibrations, and deterioration of the attaching concave part is prevented.
However, the cushion covering of the grommet of Patent Document 2 is thin-layered, and sufficient resistance to vibration cannot be expected since there is no space between the holding contact part of the main body and the thin-layered cushion.
Another problem is that it takes a long time to assemble, since after the first formation of the main body, there is required to be a second formation of the cushion layer with a thermoplastic elastomer, or it is necessary to attach the cushion layer to the main body.
Patent Document 3 discloses a pipe support device that is composed of a curved holding part having spring elasticity and a supplementary clip part that is squeezed into the middle of the curved holding part. The curved holding part is formed in a U-shape, and support arms are attached obliquely from the top of the side wall. The supplementary clip part is shaped to open upward and is made of a material having rubber elasticity. The curved side wall of the supplementary clip part is pressed down by the end of the support arm of the curved holding part. Also, there is an engaging protrusion element to engage with the curved holding part.
With the pipe supporting device of Patent Document 3, the side wall of the supplementary clip part is curved more to go along the outer diameter of the pipe and is held by the support arm. Should there be a strong force from the outside, it is of concern that the pipe can slip out of the supplementary clip part. Also, resistance to vibration is not sufficient because no space is provided in the supplementary clip part.
For these reasons, a vibration-proof clamp is needed that has a small number of vibration-proof clamp construction parts, that can be assembled easily by hand and that can be made by using an ordinary injection molding machine without using a molding machine for insert molding or dichroic molding and a complicated die. Furthermore, a satisfactory vibration-proof clamp is needed with the capability to hold a pipe.